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Status of WP4: FTIR measurements. M. De Mazière (BIRA-IASB) K. Petersen, T. Warneke, J. Notholt (U. Bremen). Ground-based FTIR network. WP4: Observations from ground networks. From DoW WP4:.
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Status of WP4: FTIR measurements M. De Mazière (BIRA-IASB) K. Petersen, T. Warneke, J. Notholt (U. Bremen)
From DoW WP4: • Perform solar absorption measurements in the mid-infrared spectral region at the 7 European NDACC stations (28°N to 80°N), throughout the duration of the project, at a minimal frequency of about 1 meas./week And perform measurements at tropical stations duringcampaigns • Optimise the retrieval of CH4 in the mid-infrared spectral region • Evaluate the error budget of CH4 and N2O vertical profiles • Provide a consistent set of total column densities and vertical profiles of CH4 and N2O for model evaluation and satellite validation • Validate and calibrate the SCIAMACHY and IASI satellite measurements
Status at KO For CH4 • Set of retrieval microwindows defined for profile retrieval • DOF 3 • Relative error on tropo- column 10% For N2O • 2 Sets of retrieval microwindows defined for profile retrieval • DOF 4.5 • Relative error on tropo- column 5 to 10% For both: Consistent timeseries at UFTIR stations (excl. tropical and ship-borne data) BUT: • Error budget ? In part. for CH4: accuracy?Cf.uncertainties on spectroscopic params. • Lack of data in tropics
(To be) done in HYMN • Continuation of measurements at the European NDACC sites : ongoing • Analysing past data at tropical stations and performing new measurement campaigns in the tropics: ongoing, esp. at Paramaribo and Ile de La Réunion • agreement to perform and report pressure measurements and/or pressure data from weather stations. • Optimisation of the total column and profile retrievals of CH4 in the mid-IR: • Analysis of new microwindow options (all) • CH4 cell measurements (Univ. Bremen and IMK-Karlsruhe) to define spectroscopic parameters results expected by July 2007 • NCEP/ECMWF data: KNMI provides ECMWF data to test sensitivity of retrieval to T-profile
(To be) done in HYMN (cont’d) • Retrieval strategy: to be homogenized as much as possible from station to station. • Provision of a consistent set of total column densities and vertical profiles of CH4 and N2O for model evaluation and satellite validation. • By September 2007: submission of preliminary historical time series in HYMN database; focus on 2004; if possible, extend from 2003 to 2006 • Archived parameters, metadata and data format have been decided: = individual profile data + averaging kernels in HDFv4.3 format, inline with AVDC guidelines • Evaluation of the error budget of vertical profile data (CH4 and N2O): while fixing retrieval strategy
(To be) done in HYMN (cont’d) • Comparisons FTIR –Model: • every group will do the comparison for its own sites! • Model data will be provided in separate files for each site (each day at 12h LT or 10-16h LT mean) • Do the modelers need info as to timing of FTIR measurements ? • Comparisons FTIR – satellite • Via model and direct FTIR-satellite • Need fro dry-air column averaged VMR ? Test at tropical stations. Next meeting in October 2007